We pick d.root-servers.net, one of the 13 root servers (1), and ask it about sv.cctld.authdns.ripe.net and learn that net is delegated to 13 name servers (2), so we ask f.gtld-servers.net where we learn that ripe.net is delegated to seven name servers, including a2.verisigndns.com (3), so we ask that one and get the following answer: